Score of Parentheses
Given a balanced parentheses string, compute its score where () is 1 and concatenation sums, nesting multiplies by 2.
Validate Stack Sequences
Given two sequences of distinct integers, verify whether the second sequence is a valid pop order for a stack given the first sequence as push order.
Buildings with ocean view
Given building heights, return sorted indices of buildings that have a clear view of the ocean to their right.
Sum of Subarray Minimums
Given an integer array, sum the minimum of all contiguous subarrays modulo 10^9+7.
Asteroid Collision
Simulate asteroid collisions with a stack and return the remaining asteroids in original order.
Decode Nested String
Implement a function that decodes a string with nested encoding patterns.
Showing 25–30 of 30 challenges
Guide: free Python coding challenges
Practice Python by solving problems
PythonSkillset challenges are hands-on coding exercises from beginner to advanced. Open a challenge, read the problem, write Python in the split-pane editor, and run tests with Pyodide — no install required.
How to use the arena
- Pick a category — basics, algorithms, strings, and more
- Open a challenge, read the statement, and edit the starter code
- Run tests, fix failures, then try a related quiz or tutorial lesson
Challenges vs tutorials and quizzes
Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.